Bears

Evaluating Predation by Bears
Grizzly bears are common in parts of Canada and Alaska but occur only in limited areas of the west in the lower 48 United States, primarily in Yellowstone Park and in northwestern Montana. They are omnivores and consume large amounts of vegetation and wild fruits in addition to carrion and prey.

Predation by black bears on livestock is most common in spring and summer. Limited food sources in early spring and failures of wild berry and nut crops during summer months are probably major contributing factors.

Bear Predation – Description

Grizzly Bears
Grizzly bears are common in parts of Canada and Alaska but occur only in limited areas of the west in the lower 48 United States, primarily in Yellowstone Park and in northwestern Montana. They are omnivores and consume large amounts of vegetation and wild fruits in addition to carrion and prey. They will take nearly any domestic animal species, but cattle and sheep are their most common livestock prey, primarily because these are the most common species available. Grizzly bears are large and powerful and generally have little trouble killing adult livestock. They kill with bites and blows to the head or neck and commonly break bones of the skull, neck or shoulders. They may leave claw marks and tooth punctures on the head, neck and back.

Grizzlies typically drag their kills into cover prior to feeding. They skin out the carcass, leaving skin and skeleton relatively intact. They do not chew and scatter bones like canids do. Commonly, they cover their kills with soil and vegetation and feed repeatedly as long as flesh remains. They readily feed on carrion, and leave extensive sign (matted vegetation, tracks and feces) around a carcass.

Black Bear
Predation by black bears on livestock is most common in spring and summer. Limited food sources in early spring and failures of wild berry and nut crops during summer months are probably major contributing factors. Black bears are also omnivorous and vegetation is a significant part of their diet. They do extensive damage in some areas of the northwestern states by stripping the bark from trees and feeding on the cambium. Black bears raid beeyards for honey and orchards for fruit. They also feed readily on carrion.

Black bears will attack adult cattle and horses but seem to prefer sheep, goats, calves and pigs. They may break the neck or back of prey with blows from the paws, but normally they kill by biting the neck and shoulders. Claw marks are frequently found on the neck, back and shoulders of these larger animals. Multiple kills of sheep and goats are relatively common, possibly because they are easy prey.

Whether by accident or design, bears have been known to frighten livestock herds over cliffs, causing injuries and death to many animals.

Black bears prefer to feed in seclusion and often drag their prey to cover. They frequently begin feeding on the udder of lactating females, but generally prefer meat to the viscera. Some begin feeding at the neck or shoulders where the initial attack occurs. Where most of the prey is consumed, the skin of large prey is stripped back and turned inside out. The skin and skeleton are usually left largely intact. The carcass is rarely scattered by black bears although this may be done by coyotes or other animals that scavenge the remains. Vegetation around the carcass is usually matted down by black bears and their droppings are frequently found nearby.

Black bears may attempt to cover remains of larger carcasses but seem somewhat less inclined to do so than cougars and grizzly bears. Bear tracks have distinct characteristics. Bears have five toes with a broad, short pad on the front foot and five toes with a triangular pad on the rear foot. The rear foot oversteps the front foot in normal travel.

This calf was attacked by a black bear which began feeding at the shoulders while the calf was still alive. the bear was shot at the site and the calf had to be destroyed

These are the tracks of a black bear made in soft soil. Note the distinct pattern of the toes and rear pads in the tracks.

This rather formless pile of scat was deposited by a black bear which had been feeding on huckleberries.

The claw marks on this tree made by a black beer may be a territorial mark.

This ewe was attacked and her udder eaten by a black bear, although the ewe escaped and survived for a short period of time.

This ewe was killed and fed upon by a black bear. It is relatively common for black bear to feed on the udders of lactating ewes.

These are the remains of a lamb that weighed approximately 70 pounds which was killed and almost entirely consumed by a black bear. The skinning of the carcass and almost total consumption indicates an adult bear’s huge appetite, as well as its feeding behavior.

After killing and eating the lamb shown in the previous illustration, the bear then killed this ewe and fed heavily on the neck and shoulders. Note the distinct difference in the feeding pattern compared to that of other carnivores.